As broadcast services having high-resolution/high quality have been generalized due to technology development, there is growing interest in ultra high definition (UHD), which has a resolution four or more times higher than high definition (HD) resolution. High dynamic range (HDR) and wider color gamut (WCG) techniques are new issues, and thus, research on next generation image technologies is actively being conducted to overcome the limitations of conventional compression technology.
In addition, there have been attempts to enhance compression efficiency in technical fields of prediction, transform, quantization, entropy encoding, etc. In order to reduce distortion, error, blocking effect, ringing effect, etc. that occurs with a reconstructed picture, applying an in-loop filter is also required to be considered in terms of enhancing compression efficiency.